1. Field of the Invention
The present invention generally relates to a headrest for use on a vehicle or automotive seat, and in particular to the structure of donut-like headrest or the so-called "see-through-type headrest" having a through-hole formed centrally thereof, which provides an aesthetically improved appearance and better permits a person to see through an opposite side of the headrest to through the through-hole.
2. Description of Prior Art
Among various kinds of headrests, a donut-like shape of headrest or the so-called "see-through-type headrest" has been made available, appealing to drivers and occupants on the automotive seat in terms of its attractive annular design and its central through-hole serving to widen the view or the field of vision, allowing an opposite side of the headrest to be easily viewed therethrough in the eyes of driver or occupant on the seat.
Conventionally, in the process of assembling this sort of headrest, it has been a common practice to use such generally inverted-U-shaped headrest frame having a cross bar frame or connecting frame extended therebetween, and place the same within a donut-like three-dimensional trim cover assembly before subjecting them all to a foaming process, as is typically known from the Japanese Laid-Open Patent Pubs. Nos. 63-290711 and 9-271425.
Reference is now made to FIG. 1 which shows a basic structure commonly obtained from the foregoing prior arts. Specifically, the headrest of this conventional kind is designated generally by (H'), which comprises a generally donut-like or annular three-dimensional trim cover assembly (2') having a through-hole (A) defined therein, a generally inverted-U-shaped headrest frame (1') whose headrest support portion (1'A) is placed and embedded in the trim cover assembly (2') integrally with a foam cushion member (3'). As shown, a pair of headrest stay portions (1'B)(1'B) of that headrest frame (1') are projected externally from the bottom wall (2'A) of trim cover assembly (2') and mounted in a seat back (SB) of vehicle or automotive seat.
In the illustrated mode of FIG. 1, there is employed such generally "U" shaped headrest frame (1') as typically seen from the Japanese Laid-Open Patent Pub. No. 63-290711, which has a pair of inwardly bent juncture points (1'C)(1'C) between the upper head support frame portion (1'A) and two straight stay portions (1'B)(1'B), with a connecting frame (12') connected between the two straight stay portions (1'B)(1'B) below the upper head support portion (1'A).
However, with this conventional headrest structure, the height-wise lower half area (W0) inevitably becomes large in relation to the whole height-wise dimension (W1) in the donut-like headrest body, because both connecting frame (12') and two inwardly bent juncture points (1'C) stated above occupy a relatively large area of headrest body below the through-hole (A), which inevitably requires enlarging the inner hollow volume of the corresponding lower half portion of trim cover assembly (1). As a consequence thereof, the through-hole (A) of resulting headrest becomes small relative to the whole area of headrest body, thus narrowing the field of vision that a driver or occupant on the seat can attain via the through-hole (A).
Further, the through-hole (A) per se must be of a certain fixed size to support the head of driver or occupant on the seat and can not be widen freely therefrom, taking into account an ordinary average size of driver's or person's head and a comfortable head support touch thereto.
The same problem as above goes for such mode of headrest as typically shown in the Japanese Laid-Open Patent Pub. No. 9-271425, which employs a genuine inverted "U" shaped headrest frame without such two inwardly bent juncture points (1'C). In this instance, a connecting frame is connected between a pair of spaced-apart straight stay portions below the inverted "U" shaped upper head support area, as a result of which, those two stay portions frame are spaced much wider from each other than the spacing of two stay portions (1'B) described above, which makes it impossible to reduce the annular dimension of headrest body in relation to the through-hole (A).
Hence, in the hitherto conventional structure of donut-like or see-through-type headrest, the whole dimensions of headrest body are inevitably large in relation to the through-hole (at A) formed centrally thereof, which prevents attaining of a wide field of vision around the headrest for a person to see the opposite side therebeyond and also imbalances the whole annular appearance of headrest body, impairing thus its outer aesthetic appearance.